Portable pipe mill

ABSTRACT

An independent self-contained portable pipe mill and method, for producing large diameter steel pipe in the field, the mill components being mounted on a plurality of vehicles, such as highway trailers, that may be moved to the desired site and there connected together when arranged in alignment and levelled in true assembly line. Provision is made for over-width components of the forming mill being mounted on turntables to enable their being rotated into longitudinal position for transporting. Novel features include equipment for handling and sizing the steel plates and square edging the same in a stack, welding apparatus, a hydraulic-mechanical end expander, a low-weight frameless hydraulic expander and a precision pipe end finisher. The mill is provided with a knockdown type enclosure and has its own fuel powered driving mechanism and electric generator.

1 1 Oct. 2, 1973 1 1 PORTABLE PIPE MILL [75] Inventor: Douglas L. Sprung, W. Vancouver,

British Columbia, Canada [73 I Assignee: International Portable Pipe Mills Ltd., Calgary, Alberta, Canada [22] Filed: June 21,1971

[21] App1.No.: 155,148

[52] US. Cl 228/15, 29/33 D, 29/477,

61/721, 228/17 [51] Int. Cl B23k 1/20 [58] Field of Search 61/721, 72.2;

[56] References Cited UNITED STATES PATENTS 3,461,540 8/1969 Rieppel et a1 l Westin et a1 219/3 Heineman 219/10 Primary Examiner-J. Spencer Overholser Assistant Examiner-Robert J. Craig AttorneyW. lrwin Haskett 1 1 ABSTRACT An independent self-contained portable pipe mill and method, for producing large diameter steel pipe in the field, the mill components being mounted on a plurality of vehicles, such as highway trailers, that may be moved to the desired site and there connected together when arranged in alignment and levelled in true assem bly line. Provision is made for over-width components of the forming mill being mounted on turntables to enable their being rotated into longitudinal position for transporting. Novel features include equipment for handling and sizing the steel plates and square edging the same in a stack, welding apparatus, a hydraulicmechanical end expander, a low-weight frameless hydraulic expander and a precision pipe end finisher. The mill is provided with a knockdown type enclosure and has its own fuel powered driving mechanism and electric generator.

6 Claims, 25 Drawing Figures PATENTEUnm 2mg SHEET F 7 I nventor DOUGLAS L. S NG M W Att ey PATENTED 21975 SHEET 2 0F 7 FIG. 2.

Inventor DQUGIIAS L, SPRUNG BY W .M'M

Attorney PATENTED SHEET 3 [IF 7 Inventor DOUGLAS L. SPRUNG /(1.9% W

Attorney PATENTEI] UCT 2M5 SHEET u [If 7 ELM Inventor DOUGLAS L. SPRUNG Attorney PATENTED 2 SHEET 6 0F 7 Inventor DOUGLAS L, SPRUNG Attorney PATENTEB 2 SHEET 7 UF 7 Inventor DOUGLAS L, SPRUNG Attorney PORTABLE PIPE MILL This invention relates to improvements in a portable pipe mill, appertaining particularly to a mill for producing large diameter pipe from steel plate or steel coils.

It is an object of the invention to provide a pipe mill the various components of which are mounted on a plurality of vehicles, such as highway trailers, that can be moved to a selected field site and there arranged in alignment, connected together and levelled in a true assembly line.

A further object of the invention is to provide a portable pipe mill comprising separable sections wherein over-width forming mill components may be mounted on turntables rotatable on vertical pivots from operable transverse to longitudinal position for transporting.

A further object of the invention is the provision of a portable mill for the production of large diameter pipe including, in addition to the usual roll forming units, a plate sizing device for machining the steel to width and capable of simultaneously square edging a plurality of plates arranged in a stack.

A further object of the invention is the provision of a portable compact line mill for the production of large diameter pipe including, in addition to the usual roll forming units, welding apparatus to successively forge weld induction heated edges of the roll, scarf the forge weld upsets, groove the forge weld both interiorly and exteriorly and finally sub arc weld to completely penetrate the induction weld.

A further object of the invention is the provision of a portable compact line mill for the production of large diameter pipe including, in addition to the usual roll forming units, and welding apparatus, a hydraulicmechanical end expander utilizing a plurality of radially extendable segments powered by hydraulic cylinders for initially expanding the diameter of both ends of a length of pipe prior to and in preparation for the expansion of the whole pipe.

A further object of the invention is the provision of a portable compact line mill for the production of large diameter pipe including, in addition to the usual roll forming units and welding apparatus a novel and remarkably low-weight, frameless hydraulic expander (and hydrotester) that employs the expander jig as the frame for both axial and radial loads. A still further object of the invention is the provision of a portable pipe mill for producing large diameter pipe wherein, welded, expanded and tested pipe is cut to length and both ends precision finished with a bevel and land, whereafter each pipe is marked for thorough individual identification.

A still further object of the invention is the provision of an independent, self-contained portable pipe mill complete with a knockdown type enclosure and its own fuel-powered driving mechanism and electric generator.

To the accomplishment of these and related objects as shall become apparent as the description proceeds, the invention resides in the construction, combination and arrangement of parts as shall be hereinafter more fully described, illustrated in the accompanying drawings and pointed out in the claims hereunto appended.

The invention will be best understood and can be more clearly described when reference is had to the drawings forming a part of this disclosure wherein like characters indicate like parts throughout the several views.

In the drawings:

FIG. I is a schematic plan view of the mill layout;

FIGS. 2 and 2A, on sheets 2 and 3, constitute an enlarged side elevation of the forming, welding and sizing stands of the forming mill assembly carried by three tandem semi-trailers connected in alignment and levelled on jacks;

FIGS. 3 and 3A, likewise on sheets 2 and 3, constitute a plan view of the forming mill;

FIGS. 4 and 5 are end and side elevations of the milling machine carriage;

FIGS. 6 and 7 are transverse elevational-section and side view of the weld stand;

FIGS. 8, 9, I0, 11 and 12 are sectional details showing the pipe weld at various stages namely, induction heated edges prior to forge welding, forge welded with upsets, upsets scarfed off, forge weld grooved and submerged arc weld respectively;

FIGS. 13 and 14 are a transverse section and a longitudinal sectional elevation of the pipe end expander;

FIG. 15 is an enlarged sectional detail of an expander segment shoe engaging a pipe end;

FIG. 16 is a side elevation of the hydraulic expander and tester;

FIG. 17 is an enlarged transverse section on line 17-I7 of FIG. 16;

FIG. 18 is a side elevational detail thereof;

FIG. 19 is a vertical longitudinal section of the expander head and hydraulic ram;

FIG. 20 is a schematic end elevation of the end beveller and cut off;

FIG. 21 is a vertical longitudinal section showing the initial plunge cut;

FIG. 22 is a similar section showing the final facing cut; and

FIG. 23 is a sectional detail of the pipe end showing the resulting bevel land. l

Mobile pipe mills known or proposed heretofore are far from adequate for producing large diameter steel pipe in the range of 32 inch to 56inch outside diameter or capable of meeting rigid performance specifications in various jurisdictions, such as those set by Canadian Standards Association, for oil, gas or water transmission in the Arctic or in temperate or tropical climates. The demand for such large diameter, high performance pipe is already great and the tremendous escalation of such demand is imminent.

To meet todays need, larger, more complete and much heavier mills are required. Accordingly, this invention is concerned with providing a portable mill comprising the necessary components mounted on a plurality of transportable vehicles that may be moved by air, water, rail, highway or overland and assembled at the site with at least some of the carrying vehicles aligned, and connected and levelled on supporting jacks in a true line mill. The excessive transportation costs of moving bulky pipe to far off locations favours the movement of the steel in plate or cold rolled form and the fabrication of the pipe in the field.

This mill calls for the establishment of an independent self-contained steel pipe mill, that has been transported to the site on appropriate vehicles, for performing with thoroughness and precision all the functions from carrying steel plate from a storage area to the initial milling bed, through all the stages of production and testing and marking and delivering finished pipe at the discharge end.

Having regard to the weight of the forming mill components, and other units, the vehicles are raised on special jacks based on the outrigger principle used by 100 ton mobile cranes and in the case of Arctic operations the jacks will have underlying suport pads with plastic insulation to retard and/or prevent injurious effect on the permafrost. In extreme temperatures the mill will be completely housed in a knock-down type, insulated enclosure.

Reference is now had to FIG. 1 of the drawings that shows a schematic plan of the mill layout. Steel plate stored say at the extreme left is moved to the milling bed 1 by a wheeled gantry crane (not shown) having a magnetic pick-up and that is freely maneuverable over the ground. From the milling bed to which further reference will be made, the plate is advanced by a magnetic type gantry crane 2 that runs on tracks 3 to entry plate table 4 and thence fed to the forming mill proper. The forming mill may be deemed to consist of some eleven major components or stands, namely pinch roll 5, edge break 6, drive I 7, drive II 8, drive III 9, fm I 10, fin II II, weld 12, size l 13, size II 14 and size III 15. In the present prefered embodiment, this forming mill is assembled on three tandem semi-trailers 16, 17 and 18 that carry stands -7, 8-11 and 12-15 respectively. Beyond the forming mill proper the weld tube or pipe is pulled out on a table 19 and here the direction of travel of the product that has been moving in a longitudinal line is altered and the pipe is rolled offlaterally on skids 20 into a holding bay and rework area 21 where the pipes can be reciprocated longitudinally on pipe carts in the submerged arc rewelding station 22 all the while progressing laterally from the run out table 19.

A new and sophisticated phase in the finishing of the product now begins. The pipe is again moved longitudinally parallel to the forming mill line on a pipe cart for the radial expansion of both ends by a mechanicalhydraulic end expander 23, see FIGS. 13, 14 and 15, and thereafter moved laterally into a frameless pipe expander andhydrotester 24, see FIGS. 16, 17, 18 and 19. Alternatively, a hydraulic-mechanical unit comparable to a modified end expander may be used to expand the entire length of the pipe.

The pipe fully expanded and tested is again run longitudinally and skidded laterally to the end beveller and cut-off 25, skidded laterally across the ultrasonic retesting station 26, reciprocated into and back out of an x-ray booth 27 and then hoisted by magnetic pick-up crane 28 and deposited on scales 29 for weighing and final precise identification marking.

Reverting now to FIGS. 4 and 5, we see the plate edger carriage 30 that runs on mill tracks 31 that taper inwardly toward the bottom and are laterally engaged on opposite sides by a confronting pair of vertically adjustable bevelled machined wheels 32.

There are two 100 HP. milling heads (not shown) adjustably mounted on this carriage movable the full length of the pile of plate on the milling bed 1 so that steel plate is simultaneously machined on opposite edges. Edge milling is superior to planing or shearing one plate at a time and in the present case the pair of millers can prepare a stack of eight Xi-Inch plates, for a depth of 6 inches at one time.

After the steel has been formed into an elongated cylinder or pipe by the time it emerges from mill stand fin II II, it passes through a Berkely Cage 35 and enters weld stand 12. By using inductor bars that localize heat at the pipe edges, the welding line can function at good speed, the operation being by 10 HZ welding supplied by rotating generators or solid state ratification and so eliminates the need for shot blasting the pipe edges.

While the relative locations of the induction bars 36 and scarfer 37 are seen in FIG. 1, the bars in advance of and the scarfer following the weld stand 12, the detailed structure of the foremost stand on semi-trailer 18 is seen in FIGS. 6 and 7. Reference should also be had to FIGS. 8 to 12 inclusive. Here in this weld stand 12 the confronting edges of the cylindricalized item under the influence of the induction bars 36 are raised to welding temperature as the twin rollers 38-39 riding the outer surface of the cylinder finally close the gap to forge a butt weld seam 40 with a ridge or an unset 41 along both outer and inner surfaces of the pipe. As the pipe proceeds through the scarfer 37, companion inside and outside diameter tools 42 and 43 remove the hot metal upset in the welding process to produce a smooth seam as seen in FIG. 10 whereafter a second set of tools is used to cut matching grooves 44 on both the outside and inside of the pipe that together reduce the remaining thickness of the tube to approximately twothirds of the normal thickness of the tube wall. Finally these grooves serve as guides for the submerged arc welding in the rewelding station 22 after the pipe is discharged laterally from the run out table 19, where the sub arc weld 45 penetrates the induction weld 40 completely in accordance with the best present day practree.

The pipe is now ready to be cold expanded, a process which can be carried out effectively in two steps employing successively the pipe end expander 23, see FIGS. 13, 14 and 15, and the frameless hydraulic expander 24, see FIGS. 16, 17, 18 and 19. The present end expander is an hydraulic-mechanical unit of relatively light weight and reasonable cost and may be used also in the fabrication of bell and spigot joints. In this instance, both ends of the pipe are to be expanded to a desired diameter and then the whole intermediate length of pipe brought up to corresponding size. The device may consist of six or eight or more segments but in the illustrated embodiment there are four such segments whose arcs describe a circle ofjust less diameter than the interior of the pipe and are formed as channels in cross section as seen in the lower half of FIG. 14 to accommodate the hydraulic plungers 51. On the exterior surface of its are each segment has an expander shoe 52 that engages the inside of the pipe and it will be noted particularly in FIG. 15 that the inner edge of the shoe is intransit with the centre line of the plunger to assure that the expansion load that maximizes at the inner hoop location 53 of the pipe end is axial to the plunger and its hydraulic cylinder to prevent distortion thereof. To limit the insertion of the apparatus in a pipe end to the desired distance say up to 6 inches a radially extending stop 54 with a screw mount 55 for longitudinal adjustment may be mounted on each segment or some of them.

Separable into a number of major components for moving, the hydraulic expander which is approximately ninety feet long weighs only seventy tons because it is frameless in that the expanding jig serves also the purpose of a frame for both axial and radial loads. The principle of operation of this novel pipe expander resides in utilizing a pipe-receiving vessel having sealed heads 61 at each end, and between these heads,

the main portion of the vessel that serves as a jig comprising a complementary pair of semi-circular shells 62 that are hingedly connected along the rear side by a hinge pin 63 located just below the horizontal transverse centre line. When the jig is closed, the operable side is locked in an overlap type joint by a pin or pins 64 level with the centre line. When a pipe whose opposite ends have been expanded as already described is lowered into the opened jig 60 with its weld line showing, the pipe-sealing inner end 65 ofa ram 66, normally retracted into the sealed head 6K of the vessel, is intro duced into the expanded end of the pipe, as seen best in the enlarged section of FIG. 10. Then the upper half ofthe jig is closed and locked, hydraulic pressure is applied through ports 67 in the vessel heads to the outer end of the ram 66 and through conduits 68 in the ram into the interior of the pipe so that the entire length of pipe is expanded into the restraining jig. There may be perceptible shortening of the pipe at this time but the rams, because the area is larger at the outer end, automatically move in as the pipe length reduces yet are restrained in travel by the pipe to be expanded. On completion of the expansion operation which serves to raise the yield point of the metal, pressure is released and the top half of the jig shell is opened and the pipe repressured, at a lower pressure than for expansion, for testing and the longitudinal weld is inspected for leaks. Next the pipe is returned to the main lateral skid line for end finishing with a bevel and land. Here the pipe, as seen schematically in FIG. 20, is supported on a pair of turning rollers 70 and as it is rotated a first carbide cutting tool 71 makes a V-shaped plunge cut, as seen in FIG. 21, to provide a bevel 72 and then a second tool 73 having a flat face makes a facing cut, as seen in FIG. 22 to provide a land 74. This is now-line pipe ready for welding into a pipeline.

It is desirable, however, that each length of pipe be given an ultrasonic retest and an x-r ay to discover any laminations in the steel and identify any substandard areas. All test results are recorded and each piece of pipe, with its longitudinal centre clearly indicated, is weighed, measured and marked with length, weight, type of steel applicable code markings and serial number and when finally inspected and graded is passed out of the mill for storage.

In summary, it will be apparent that the present concept of a practical, portable pipe mill for producing large diameter steel pipe offers very substantial advantages in reduced transportation costs and faster delivery of the product at distant and relatively inaccessible locations. Critical to the provision of this desirable re sult is the strikingly novel structures employed in the over-all mill such as the miller for precision edging both sides of a stack of plates simultaneously, a compact and durable induction welder using a pair of induction bars arranged as concentrating segments in V formation, H current, hydraulic-mechanical end expanders and the frameless hydraulic jig and others. No less important to the achievement of a portable mill of such capacity is the scheme of mounting all the units on vehicles such as tandem semi-trailers with the mill components being separable in some case or rotatably mounted as on turntables to enable the vehicle dimensions and weights to comply with conventional traffic regulations: And finally, the assembly of the mill with all its ancillary mechanical and electrical power supply wherein the several vehicles, such as those carrying the forming mill units are aligned and rigidly connected in true line by connectors such as the plates 80 and 81 5 joining the tops and sides of the vehicle bed frame lbeams 82, and levelled on outrigger type jacks 83 with large support pads 84 underlayed with theremal insulation material 85, as seen in FIGS. 2A and 3A.

Various changes in the size, shape and arrangement of parts may be made to the form of invention herein shown and described, without departing from the spirit of the invention or scope of the claims.

What is claimed is:

I. An independent, self-contained, portable pipe mill for producing large diameter pipe, comprising pipe mill components mounted on a plurality of vehicles that can be individually moved to a distant site inaccessible by road or rail and there certain of the vehicles arranged in alignment, means rigidly connecting frames of said vehicles in longitudinal alignment, and outrigger type jack means having large supporting pads and underlayed with thermal insulation for levelling said vehicles to provide a longitudinally and vertically true assembly line.

2. A portable pipe mill according to claim 1, wherein at least some of said pipe mill components are mounted on turntables carried on the vehicles and are horizontally rotatable from longitudinal transporting to transverse operating position.

3. A portable pipe mill according to claim 1, wherein said mill components include an edge miller with a pair of carriage-mounted milling heads capable of simultaneously machining both edges of a stack of steel in readiness for being rolled in to pipe and a precision pipe and finisher for axially rotating a pipe with cutting tools for making sucessively a plunge cut and a face cut to form a bevel and land on the pipe end.

4. A portable pipe mill according to claim 1, wherein the vehicle-carried pipe mill components include in combination with the usual forming mill units, a weld stand with a spaced pair of rollers for finally closing the gapin the pipe cylinder and forging a butt weld seam, a pair of induction bars in advance of the stand, a supply of IO ll-IZ current thereto for localizing heating of the aboutto-be-forged cylinder edge to welding temperature and a scarfer with companion inside and outside diameter tools for removing hot metal upset on both inside and outside of the weld seam.

5. A portable pipe mill according to claim I, comprising in combination with the vehicle-carried pipe mill components whose transporting vehicles are arranged in alignment, connected and levelled, a plurality of pipe handling components arranged in lateral extension from the delivery end of the said assembly line of components on the aligned and connected vehicles which includes submerge arc rewelding; pipe end expander; hydraulic pipe expander; end beveller; ultrasonic and x-ray testing; pipe weighing and marking stations.

6. The combination with the pipe mill according to claim 5, including track-carried gantry cranes with magnetic pick-ups moveable over the said assembly line and the arrangement extending laterally therefrom,

respectively. 

1. An independent, self-contained, portable pipe mill for producing large diameter pipe, comprising pipe mill components mounted on a plurality of vehicles that can be individually moved to a distant site inaccessible by road or rail and there certain of the vehicles arranged in alignment, means rigidly connecting frames of said vehicles in longitudinal alignment, aNd outrigger type jack means having large supporting pads and underlayed with thermal insulation for levelling said vehicles to provide a longitudinally and vertically true assembly line.
 2. A portable pipe mill according to claim 1, wherein at least some of said pipe mill components are mounted on turntables carried on the vehicles and are horizontally rotatable from longitudinal transporting to transverse operating position.
 3. A portable pipe mill according to claim 1, wherein said mill components include an edge miller with a pair of carriage-mounted milling heads capable of simultaneously machining both edges of a stack of steel in readiness for being rolled in to pipe and a precision pipe and finisher for axially rotating a pipe with cutting tools for making sucessively a plunge cut and a face cut to form a bevel and land on the pipe end.
 4. A portable pipe mill according to claim 1, wherein the vehicle-carried pipe mill components include in combination with the usual forming mill units, a weld stand with a spaced pair of rollers for finally closing the gap in the pipe cylinder and forging a butt weld seam, a pair of induction bars in advance of the stand, a supply of 10 HZ current thereto for localizing heating of the about-to-be-forged cylinder edge to welding temperature and a scarfer with companion inside and outside diameter tools for removing hot metal upset on both inside and outside of the weld seam.
 5. A portable pipe mill according to claim 1, comprising in combination with the vehicle-carried pipe mill components whose transporting vehicles are arranged in alignment, connected and levelled, a plurality of pipe handling components arranged in lateral extension from the delivery end of the said assembly line of components on the aligned and connected vehicles which includes submerge arc rewelding; pipe end expander; hydraulic pipe expander; end beveller; ultrasonic and x-ray testing; pipe weighing and marking stations.
 6. The combination with the pipe mill according to claim 5, including track-carried gantry cranes with magnetic pick-ups moveable over the said assembly line and the arrangement extending laterally therefrom, respectively. 